Stinging Nettle Root for Androgenetic Alopecia
Verdict: Insufficient Evidence
Across 4 PubMed studies, the evidence for Stinging Nettle Root in Androgenetic Alopecia grades Tier U — unverified / insufficient. Research is still too limited to draw a firm conclusion.
U ⚫ U Unverified Insufficient Evidence
Why this grade7-layer evidence engine
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Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.45
D
C
B
A
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← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
U · Insufficient Evidence
Confidence
79%
Broadly consistent
Evidence level
E7
Single small RCT
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.453
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — | C→U 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (4)L2 · primary research & systematic reviews
A proprietary herbal extract against hair loss in androgenetic alopecia and telogen effluvium: a placebo-controlled, single-blind, clinical-instrumental study
Finding: The active multi-herb shampoo+lotion (a 6-botanical proprietary formula that INCLUDES Urtica dioica plus Serenoa repens and others) outperformed placebo at every timepoint with significantly improved anagen/telogen ratios, but the effect cannot be attributed to nettle specifically because it is a combination product.
View on PubMed Inhibition of 5alpha-reductase and aromatase by PHL-00801 (Prostatonin), a combination of PY102 (Pygeum africanum) and UR102 (Urtica dioica) extracts
Finding: Nettle extract UR102 was a very weak 5alpha-reductase inhibitor, active only at >=12 mg/mL (ED50 14.7 mg/mL) vs Pygeum's ED50 0.78 mg/mL; for aromatase UR102 ED50 was 3.58 mg/mL and the Pygeum+nettle combination was synergistic (ED50 0.24 mg/mL, p=0.05) — all in a BPH context, concentrations unachievable at the hair follicle in vivo.
View on PubMed Urtica dioica extract downregulates the gene expression of 5alpha-RII in HaCaT cells: possible implications against androgenic skin diseases
Finding: Urtica dioica LEAF extract (not root) significantly downregulated 5alpha-RII gene expression in HaCaT cells (p=0.0021; fold change 0.5873+/-0.0586), a mechanistic signal only — no human, animal, or functional hair-growth outcome.
View on PubMed Computational drug discovery of potential 5alpha-reductase phytochemical inhibitors and hair growth promotion using in silico techniques
Finding: Molecular-docking screen flagged 6 phytochemicals (incl. chlorogenic acid and rutin from Urtica dioica) as binding 5alpha-reductase, with jamogenin strongest; purely computational with no in vitro/in vivo/human confirmation, so it generates a hypothesis rather than evidence of efficacy.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Cautious
L4b EU EFSA
Against
1548 botanical-related claims have been put on hold pending for the Commission and Member States final consideration source↗
L4d TW TFDA / 衛福部
Neutral
中文品名：蕁麻；英文品名：Stinging Nettle；學名：Urtica dioica L.；可使用部位：根、莖、葉；分類：草、木本植物類(2)可供直接食用 source↗
L4e WHO
Neutral
Radix Urticae — WHO monographs on selected medicinal plants, Volume 2 source↗
L5a NIH Office of Dietary Supplements
Cautious
There is some limited evidence that Urtica dioica (stinging nettle), alone or in combination with saw palmetto, and Pygeum africanum (African plum tree) may improve some symptoms of BPH. Urtica dioica seems to be generally well-tolerated in clinical trials and may produce mild gastrointestinal effects. Urtica dioica contains tannins, which can interact with a concomitant intake of iron, causing… source↗